<?php
function double($i) {
	return $i * 2;
}
$b = $a = 5; /* assign the value five into the variable $a and $b */
$c = $a ++; /*
            * post-increment, assign original value of $a (5) to $c
            */
$e = $d = ++ $b; /*
                 * pre-increment, assign the incremented value of $b (6) to $d
                 * and $e
                 */

/* at this point, both $d and $e are equal to 6 */

$f = double ( $d ++ ); /*
                    * assign twice the value of $d before the increment, 2*6 =
                    * 12 to $f
                    */
$g = double ( ++ $e ); /*
                    * assign twice the value of $e after the increment, 2*7 = 14
                    * to $g
                    */
$h = $g += 10; /*
                * first, $g is incremented by 10 and ends with the value of 24.
                * the value of the assignment (24) is then assigned into $h, and
                * $h ends with the value of 24 as well.
                */
?> 